Dear Josef and Keith,
thank you both for your suggestions. I think intersect would be what I want
for it makes clean code.
I have, however, spotted the problem:
I was mistakenly under the assumption that random_integers returns unique
entries, which is of course not guaranteed, so that the random sample
contained duplicate entries.
That's why the numpy methods returned results inconsistent with python 'in'.
I'll have to be a bit smarter in the generation of the random sample. Good
thing I try to do things in two different ways. (Sometimes it is, anyway...)
Thanks again for your quick help.
Cheers,
Jan
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